The magnitude of vectors $\overrightarrow {OA} $, $\overrightarrow {OB} $ and $\overrightarrow {OC} $ in the given figure are equal. The direction of $\overrightarrow {OA} $ + $\overrightarrow {OB} $ $-$ $\overrightarrow {OC} $ with x-axis will be :
${\tan ^{ - 1}}{{(1 - \sqrt 3 - \sqrt 2 )} \over {(1 + \sqrt 3 + \sqrt 2 )}}$
${\tan ^{ - 1}}{{(\sqrt 3 - 1 + \sqrt 2 )} \over {(1 + \sqrt 3 - \sqrt 2 )}}$
${\tan ^{ - 1}}{{(\sqrt 3 - 1 + \sqrt 2 )} \over {(1 - \sqrt 3 + \sqrt 2 )}}$
${\tan ^{ - 1}}{{(1 + \sqrt 3 - \sqrt 2 )} \over {(1 - \sqrt 3 - \sqrt 2 )}}$
